Variable choke mechanism for expeller presses



April 1942- R. T. ANDERSON 2,280,880

VARIABLE CHOKE MECHANISM FOR EXPELLER PRESSES Filed Jan. 26, 1940 2Sheets-Sheet l N N l 1 8 m -n mq-n F I 2 Q v I l 9! 8 o i I g" E K .5 Na I a l INVENTOR RAYMOND T. ANDERSON April 28, 1942. R. T. ANDERSON2,280,880

VARIABLE CHOKE MECHANISM FOR EXPELLER PRESSES Filed Jan. 26, 1940 2Sheets-Sheet 2 INVENTOR RAYMOND T. ANDERSON" %IA "m4 ATTORNE PatentedApr. 28, 1942 VARIABLE CHOKE MECHANISM FOR EXPELLER PRESSES Raymond T.Anderson, Berea, Ohio, assignor to The V. D. Anderson Company,Cleveland, Ohio, a corporation of Ohio Application January 26, 1940,Serial No. 315,660

4 Claims.

This invention relates to expeller presses of the worm type, such as areused for expressing oil from proteinaceous, oleaginous material, ofeither vegetable or animal origin. Presses of this kind are employed,for example, in the extraction of oil from cotton seed, copra,cracklings, or the like.

In such presses the outlet from the oil expressing chamber or channel isusually more or less restricted and is frequently adjustable as to sizeso as to retard the discharge of the more or less solid cake inaccordance with the desired results, restriction of the outlet buildingup, backwardly through the press and against the advancing stream ofmaterial being processed, that compression which is necessary not onlyto expel the oil but also to prevent the formation of cavities in themass or any release of pressure which might permit reabsorption of theoil by the cake before it is drained off or otherwise separated.

One object of the present invention is to provide an improved form ofchoke for a press of this kind, and more particularly one whose chokingeffect conveniently may be varied or adjusted, while the press is inoperation, for the purpose of adapting the press to widely differingmaterials or to variations in the characteristics or conditions of anyparticular material being processed, or to secure any desirable ultimateoil expressing or expelling effect.

Another object of the invention is to provide an improved choke for apress of this kind, which choke itself is of worm or screw form andthereby inherently, and no matter what its form or proportion or itsrelation to the barrel, may produce variable choking effects in responseto variations in its speed of rotation, or possibly more accurately, inresponse to variations in the relative speeds of rotation of th worms ofthe choke itself and of the last oil expelling unit of the press.

Still another object of the invention is to provide an improved choke ofthis kind whose driving means may be associated with the press drivingmeans for automatic control of both, so that the machine as a whole,when once set or adjusted to selected standardized conditions orresults, automatically accommodates itself to variations in thecharacteristics or conditions of the material being processed, to theend of maintaining uniform extracting effects without attention by theoperator.

Further objects of the invention are in part obvious and in part willappear more in detail hereinafter.

In the drawings Fig. 1 represents a longitudinal sectional elevationthrough one form of press embodying the invention; Fig. 2 is a detailview, corresponding to Fig. 1, and illustrating the driving mechanismfor the choke worm; Fig. 3 is another view, corresponding to Fig. l, andillustrating still another embodiment of the invention; and Fig. 4 is awiring diagram.

Referring now to the drawings, since the present invention relatesprimarily to the choke or choking mechanism, to the control andadjustment thereof, and to the utilization of choke adjustment or effectfor the purpose of controlling the operation of the expressing effectsin earlier stages of the press, the particular construction andarrangement of the screw press itself is not essential and requires noextended description. In other words, any form of continuous screw presssuch as has been used for the extraction of oil from proteinaoeousoleaginous materials of either animal or vegetable origin may beemployed for this invention.

The press shown in Fig. 1, generally speaking, is of the general typeillustrated and described in my prior application for Press and methodof operating the same, filed June 24, 1938, Serial No. 215,683, to whichreference may be had for a more complete description if desirable ornecessary.

The material to be processed, according to its nature or kind, isusually subjected to a conditioning process to more or less standardizeit so that all material going through the press on a given run will havesubstantially the same characteristics. Particularly is that true as tothe degree of cooking (if cooking is desirable), the temperature and themoisture content. 4 Ma terial to be processed, preconditioned asdescribed, is delivered or supplied to one or a plurality of expressingworms, the flight or flights of which rotate in foraminous barrels,through the openings or interstices of which the extracted oil isexpelled or discharged. As the material moves along through the press,from its inlet to its outlet, the pressure applied to the material isgradually increased, preferably also without any diminution of pressureat any time until the outlet is reached. That is to say, the pressure isbuilt up progressively by stages in any suitable manner. That may beaccomplished, for example, in a continuous screw press, by graduallyincreasing the external diameter of the shaft supporting the wormflights, by increasing the thickness or size of the vane of the wormflight itself, by gradually reducing the internal diameter of theforaminous barrel which surrounds the worm, by gradually, or by steps,reducing the pitch or degree of inclination of the worm flight, or byother suitable means to the same end. All such means gradually reduces,toward the outlet of the press, the unit of volume per unit of length ofthe worm shaft available to receive, hold, and conduct the material tobe processed. By crowding it along in a more or less graduallyconstricted channel, the pressure applied to the material increases andits bulk decreases, always with due allowance for the volume of the oilactually expelled from the barrel.

In the form shown in Fig. 1, the preconditioned material, after leavingthe conditioner shown conventionally at I, is supplied by a worm 2 to afeed hopper 3 in which rotates a worm 4 on a shaft 5. The barrel 6 inwhich the worm 2 rotates may be foraminous so that some oil expulsionoccurs here, reducing the task in succeeding stages.

Beyond the feed hopper 3, the barrel of which may be imperforate, thechannel for the material continues through a feed press marked generallyI, having a perforate or foraminous barrel 8 mounted in a suitablesupporting cage 9, and in which barrel rotate the longitudinally spacedflights In of the expressing worm. In this feed press, by dueconstriction of the channel in the manner before described, the materialis subjected to a further increase in pressure, resulting in theexpulsion of more oil as the result of the application of increasedpressure.

From the feed press 1 the material being processed, and still underpressure, with a part of the oil removed therefrom, is discharged intothe feeding or inlet end of a main press H, where it encounters thematerial-advancing and pressure increasing effect of a series oflongitudinally spaced worm flights 12. As in the feed press, the wormflights here advance the material, increase the pressure thereon andexpel further oil, which is discharged through the openings of theforaminous barrel.

Wherever it is desirable to cause expulsion of oil through the barrel-atany stage of advance of the material, the barrel is made perforate orforaminous, either by the provision of simple openings through thebarrel wall, as at it in the barrel 6, or the barrel may be made, forexample, of closely spaced longitudinall extending parallel heavy bars,as indicated at M, in the main press I I and feed press I. In the mainpress, for example, the barrel is of the bar form described and thenarrow slots forming the perforations extend across the receiving endportion of the main press and clear through said press right up to thedischarge point indicated generally at A, Fig. 1. Also, where the barrelis of foraminous form suitable means is provided for in any mannerpreventing rotation of the material with the flights of the worm shaft,such as the stop abutments shown in the form of heavy screws, as at ISin the feed press, or the knives l 56 forming similar stop abutments inthe main press.

As described in my prior application referred to, by rotating each wormor worm section at a speed suitably related to the speed of rotation ofthe worm or worm section which precedes it, with due regard forconstriction of the material conveying passage in any of the ways beforedescribed, the press so far described, as a whole, may be so operatedthat each worm or worm section supplies material to the following wormor worm section as fast as the latter will accept and advance it, thusnot only building up or gradually increasing the pressure upon thematerial toward the outlet end of the press, but maintaining thatpressure without diminution at any time and avoiding any possiblereabsorption by the cake of the oil after the latter has been expelledin liquid form.

In the present press, however, operating as described, one importantfactor in controlling the expressing worms and their effect upon thematerial is the choke or choking device, which is here of special form.Instead of consisting of several parts, such as bars, adjustable tovarious positions to more or less restrict the outlet opening, andstationary during press operation, the choking mechanism here includes amember which is movable during press operation, to wit, one or more wormflights rotating in a barrel by means capable of adjustment to vary thespeed of rotation. This choking worm is located in the discharge passagebeyond the terminal of the final expressing worm and its foraminousbarrel, that is, beyond the point A in Fig. 1. The axis of the chokingworm may coincide with the axis of the final expressing worm, as willlater appear, or may intersect said axis at any suitable angle. Witheither arrangement the worm or screw may consist of two or more flightswith stop abutments l5 located in the spaces between flights to enhancethe resistance to flow, as shown in Fig. 3. Fig. 1 shows an arrangementin Which the axis of the choking worm intersects the axis of the finalexpressing worm of the main press at an obtuse angle, say The expressingworm here comprises a shaft IS carrying a single worm flight H andextending through a wall of the casing (preferably suitably packed) tothe outside thereof for connection to an operating drive mechanism to bedescribed.

Since no expression of oil from the cake is intended to take placebeyond the outlet A, for the reason that when the cake passes this pointthe oil content has already been reduced to the desirable low value, thebarrel I8 in which the choking worm rotates is imperforate.

Assuming the press in operation with the shafts of the preliminarypress, feed press and main press all rotating and with material movingalong to and through the outlet, it is quite clear that if the chokingworm l6, ii is permited to remain stationary the helical passage alongand between the flights of the worm is so tortuous that with theinternal surface of the barrel its wall surfaces offer very greatresistance to travel of the cake, so much as to probably entirely blockits advance. As a result the cake would become a solid immovable mass inthe zone of the choking worm and form a plug stopping up the press andultimately causing it to cease operation. As a result, it is necessaryto reduce the friction through the channel of the choking worm byrotating said worm in the proper direction toproduce and promote advanceof the material, but nevertheless at a rate of speed suflicient toproduce and maintain the maximum pressure to which the material shouldbe subjected at the outlet, to thereby create and build up pressurethrough the press clear back to the feed opening of the first expressingelement thereof, such as the preliminary press 2.

The driver for the choke worm therefore preferably is one which runs ata selected constant speed Within a certain speed range, but which isprovided with means for manually varying the speed within that range.Obviously, by rotating the choking worm at different speeds, accordingto variations in thedensity of the material being processed,particularly by the time it reaches the choking device, it is possibleto set or adjust the press to meet any desirable conditions orrequirements. Adjustment of the speed of worm rotation to any desiredvalue within reasonable limits may be secured manually by suitable speedchanging mechanism, such as a Reeves drive,

but for purposes of illustration, the drawings show the shaft of theworm I6 connected by bevel gearing, represented generally at l9, and anintermediate shaft 19a, to the shaft 20 of a variable speed D. C.electric motor 2! provided with adjustable resistance coils (not shown)by means of which its speed be manually adjusted to the desired value.

Assuming the choke worm to be driven in the manner described, such as bya variable speed D. C. motor with manually adjustable resistance coils,it is clear that the controller for said resistance coils may be set toa definite position which will produce rotation of the choke worm at adefinite speed; that such speed determines, evaluates or standardizesthe choking effect of the worm, or, in other words, its resistance orimpedance to the flow of cake through or along the worm to the finaloutlet; and that at any particular controller position the press in onesense operates as though the cake were bein crowded continually througha fixed orifice of uniform unvarying size with the load resistance atthe choke maintained uniform. The uniform effect at the choke may betaken advantage of, and in this invention is taken advantage of, as ameans for controlling operation of the main press driver, which may beof any suitable type and character adapted to automatically accommodateitself to its required duty. In the arrangement shown in Fig. l, themotor 22 is an alternating current slip ring motor, the wiring diagramof which is illustrated in Fig. 4. As shown, said motor is provided withdelta connected stator windings 23 which cooperate with a Y-connectedrotor winding 24 connected through slip rings 25 to manually adjustableresistance coils 26 also Y-connected. This motor 22 inherently has theability to automatically accommodate itself to conditions at the chokeand particularly to automatically adjust its own speed for the purposeof maintaining uniform torque. As a consequence, it rotates the worm ofthe main press ata rate of speed which not only completes expressing ofthe oil from the material undergoing treatment, but also delivers thecake to the choke worm just as fast as the latter will accept and passthe cake to the final outlet, as will be readily understood.

Likewise, the feeding press I may be driven by its own motor, of similarslip ring type, so as to feed material to the main press as fast as thelatter will accept it, automatically accommodating its speed to the dutyrequired. Or, the feed press I may be driven by the same motor 22through a slip clutch connection, such as described in Anderson Patent1,971,632, granted August 28, 1934, for Feeding mechanism for presses.

Of course, in the arrangement shown in Fig. l, the direction of travelor movement of the cake changes at the point A, or just beyond it, whereit moves into the barrel of the inclined choking worm. To assist inconforming the material to its new channel the extreme end of the wormshaft of the main press may be provided with one or more breakers 21,which are simple projections rotating with the worm shaft and tending tochurn or break up the cake and prevent it from becoming packed orjammed.

Fig. 3 illustrates another arrangement in which the choke worm flightIla. rotates on the same axis as the axis of the worm or screw Ha of themain press, worm flight Ha being in the form of a screw carried by asleeve 30 rotating on the shaft of the main worm and driven by gearing3i from the motor Zia, similar in construction and manner and method ofcontrol to the motor 2|. In this form the material passes along from themain press to the choke Worm 3'3, whose speed is selected in accordancewith the density of cake to be obtained; As it moves along with theworm, it finally reaches a channel 32 leading to a suitable dischargepoint.

With both arrangements described the speed of rotation of the choke wormdetermines or evaluates the choking or resistance effect at the pressoutlet. In each case the speed of rotation of the choke worm may bemanually set or adjusted at any value by regulation of the controllerfor the worm driver, and when the speed has once been set the choke wormwill continue to rotate at that speed. The choke worm may also serve asa controller for the next worm preceding it, to-wit, the worm of themain press, and the latter in turn may control its predecessor worm,such as the worm of the feeding press. The net result of theconstruction is to gradually apply an increased compression to thematerial being processed from the time it leaves the conditioner clearto the discharge-of the cake from the press, the oil having been removedgradually during progress of the material through the press. Conditionsare maintained uniform throughout the press with production of maximumefiiciency and a uniform and high quality product.

What I claim is:

l. A continuous press of the character described, comprising anexpressing worm, a choking screw cooperating therewith, and operatingmeans for said worm and screw arranged to cause the speed of one thereofto control the speed of the other and thereby maintain uniform loadconditions throughout a period of operation.

2. A continuous press of the character described, comprising anexpressing worm, a choking screw cooperating therewith, means forrotating one thereof at substantially uniform speed, and variable speedrotating means for the other thereof, whereby the speed of the lattermay be accommodated to the speed of the former, for the maintenance ofuniform load conditions throughout a selected period of operation.

3. A continuous screw press, comprising an expressing worm, a foraminousbarrel therefor, a choke worm, means for rotating said choke worm at apredetermined speed to produce a desired choking effect, and operatingmeans for the expressing worm the speed of said operating means varyingin response to changes in the resistance of said choke worm to travel ofthe material being processed.

4. A continuous press of the character described including a main pressand a choking device, an expressing worm for advancing material throughsaid main press and delivering it to said choking device, a choke wormfor advancing material through said choking device, uniform torquedriving means for said main press worm, driving means for said chokeworm capable of adjustment to operate at a desirable substantialconstant speed, and means for adjusting the rotational rate of saidchoke worm in a manner to retard to a desirable degree discharge fromsaid continuous press to thereby build up and maintain pressure upon thematerial being processed.

RAYMOCND T. ANDERSON.

